Tile Layout Start Point Calculator
A clean tile job depends on where you start. Begin flush at one wall and you often end with an ugly sliver of cut tile at the far wall. Centering the layout instead splits the leftover space into two equal, larger edge pieces. This calculator works along one run of the room. Enter the run length, the tile size, and the grout joint width in inches. It returns how many full tiles fit, the width of the centered edge cut on each side, and whether shifting the layout by half a tile gives a more balanced result.
Tile layout start point formula
Repeat = tile size + grout joint
Full tiles = floor(run / repeat)
Leftover = run - full tiles * repeat
Centered edge cut = leftover / 2
Half-tile shift cut = (leftover + repeat) / 2, capped to one tile
The repeat distance is one tile plus one grout line. Centering splits the leftover into two equal edge pieces. Shifting by half a tile can turn a thin sliver into a more balanced edge.
Tile layout tips
- Avoid edge pieces narrower than about half a tile; they look awkward and crack easily.
- The grout joint is part of the repeat: a wider joint means fewer full tiles.
- Plan each room direction separately, then mark layout lines from the centre.
- Dry-lay a row before fixing to confirm the edge cuts match the calculation.
- ANSI A108 and TCNA installation standards govern tile layout and joint practice in the US.
Tile layout: frequently asked questions
Why does the tile layout start point matter?
Starting tiles flush against one wall often leaves a thin sliver of cut tile at the opposite wall, which looks bad and is hard to cut. Centering the layout balances the cut tiles on both edges so each side gets a larger, symmetric piece.
How is the edge cut tile width calculated?
Each tile occupies its width plus one grout line. The number of full tiles is the floor of the run divided by that repeat distance. The leftover space, split between two edges when centered, gives the cut tile width on each side.
Should I center on the tile or on the grout joint?
If the leftover edge piece would be very small (a thin sliver), shifting the layout by half a tile moves a full tile to the edge instead, leaving a more balanced cut. This calculator reports both the centered edge cut and whether a half-tile shift improves it.
Does grout line width affect the layout?
Yes. The repeat distance is tile size plus grout joint width, so a wider grout line means fewer tiles fit across a run. This calculator includes the grout joint in every calculation.
What is a good minimum edge tile width?
Many tile setters avoid edge pieces narrower than about a third to a half of a full tile because slivers are fragile and visually awkward. This calculator flags when the centered edge cut is below half a tile so you can consider shifting the layout.
Official sources
- U.S. General Services Administration: Design and construction standards.
- American National Standards Institute: ANSI A108 ceramic tile installation standards.
Reviewed by the CalculatorHub team, edited by James Graham, 16 June 2026. See our methodology.